The present invention relates generally to post-production testing procedures, and more particularly to verifying connectivity and continuity of a digital bus used in a computer.
FIG. 1 is a block schematic diagram of a conventional testing configuration 10 for testing connectivity and continuity of a bus under test (B.U.T.) 12 that connects a bus interface device 14 to a bus connector 16. BUT 12, device 14, and bus connector 16 are assembled on a system board 20. In certain applications, a host bus 22 couples device 14 to a central processing unit 24 that may or may not be integrated on system board 20. Device 14 provides interface control information and signals for communicating with a bus device 26 coupled to bus connector 16 by a bus 28.
In operation, CPU 24 accesses information from bus device 26 by issuing appropriate instructions to device 14. Device 14 translates the instructions into bus commands appropriate for the type of bus coupling device 14 to bus device 26. For proper operation, BUT 12 must be properly wired to connector 16. When testing an assembled system board 20, there are many tests that are performed. One fundamental test that is performed is to verify connectivity (proper wiring and continuity of the wiring) of BUT 12 between device 14 and connector 16. As system board 20 becomes complex, and because device 14 is a semiconductor device mounted or otherwise affixed to system board 20, it becomes increasingly difficult to verify proper connectivity of BUT 12.
For example, BUT 12 may be a Small Computer System Interface (SCSI) bus and device 14 would be a SCSI controller. For a conventional post-production test of the connectivity of the SCSI bus, a SCSI device (for bus device 26) such as a SCSI versions of a hard disk, printer, tape drive CD ROM, scanner, etc. is coupled to bus connector 16 using an appropriate cable for bus 28. Then, proper power, termination, and control signals must be provided as well known in order to operate the SCSI device. The results of operating the SCSI device must be interpreted by the testing program to determine whether BUT 12 is properly connected between device 14 and connector 16.
Unfortunately, there are many reasons for such a prior art test to fail that are not related to connectivity of BUT 12. Additionally, testing BUT 12 for connectivity using such a conventional system is inefficient as acquiring, connecting, powering up, and properly configuring SCSI device 26 and system board 20 are non-trivial tasks.
While the specific example was explained in terms of a SCSI bus, other common buses used in the computer environment experience similar types of inefficiencies when performing post-production connectivity testing. Some of the other types of buses include industry standard architecture (ISA), enhanced or extended ISA (EISA), microchannel, peripheral component interface (PCI), VESA, NU-Bus, etc.